Suction gathering glass mold



Jan. 23, 1951' G. R. BOWE, JR

SUCTION GATHERING GLASS MOLD Original Filed April 17, 1945 Patented Jan. 23, 1951 SUCTION GATHERING GLASS MOLD George R. Bowe, in, South Bend, Ind., assignor, by mesnc assignments, to Owens-Illinois Glass Company, Toledo, Ohio, a corporation of Ohio Original application April 17, 1943, Serial No. 483,433. Divided and this application February 19, 1947, Serial No. 729,493

8 Claims.

My invention relates to apparatus for gathering mold charges or blanks of glass by suction into a gathering mold or cup from a pool of the molten glass.

One of the principal methods in use at the present time, known as the suction method, for segregating mold charges or gobs of glass from a molten supply body, consists in lowering a gathering mold open at its lower end, into sealing contact with a pool or body of molten glass, filling the cavity by suction, lifting the mold and severing the gathering glass from the supply body, as by means of a knife or shears.

When the mold is lifted from the surface of the pool, a column of glass uniting the gathered charge with the glass in the pool, is drawn upward with the mold, owing to the viscous nature of the glass. This column is ordinarily of substantially the same diameter as the bottom opening through which the charge of glass is drawn into the mold cavity, except that when the mold is lifted a considerable distance above the pool before the glass is severed, there is a certain amount of necking-in or constriction of the column of glass at a distance below the mold. When.

this column of glass is severed from the gathered charge, the glass is chilled by the knife or shears and a so-called cut-off scar is produced at the plane of severance. This scar usually appears as a defect in the finished ware, as the blowing, or molding operation does not fully eliminate the" scar. Numerous expedients have been resorted to in an endeavor to overcome this difliculty, many of them involving reheating operations and other methods and means for removing or reducing the scar.

An object of the present invention is to provide a novel suction gathering mold and cooperating means for effecting a necking-in or constriction of the column of lass immediately below the,

gathering mold when the latter is withdrawn from the supply body, and thereby greatly reducing the cross-sectional area of the glass at the plane of severance. In this manner the severing of the glass is greatly facilitated and the area of chilled;

further permits the production of mold charges or blanks which may be fabricated into finished articles by methods which are impractical when the usual cut off scars are present.

Other objects of the invention will appear hereinafter.

The present application is a division of my copending application for Suction Methods of Gathering Molten Glass, Serial Number 483,433, on which Patent No. 2,425,592 was granted August 12, 1947.

Referring to the accompanying drawings which illustrate a suction gathering mold constructed in accordance with my invention:

Fig. 1 is a bottom plan view of the mold;

Fig. 2 is a sectional elevation of the same;

Figs. 3 and 4 illustrate steps in the method of gathering a charge of glass. Fig. 3 shows the mold in sealing contact with the pool of glass and the mold cavity filled by suction. Fig. 4 shows the mold with its charge lifted away from the pool and the column of glass necked-in prior to severance; and

Fig. 5 is a view similar to Fig. 4 but showing a ewhat modified construction by which a flange or lip may be produced on the lower end of the mold charge.

The mold comprises a body Hi and a diskshaped plate ll attached to the bottom surface of said body, said parts made of iron or other suitable metal. The mold is attached to the lower end of a tubular gathering spindle !2. The mold is form d with a downwardly opening cavity is. An annular vacuum groove l4 surrounding the mold cavity is formed by cutting away a portion from the upper surface of the disk. Vertical, radially disposed vacuum slots are cut in the mold cavity wall surface E6 of the plate H, said slots being arranged in an annular series. A series of feeding vacuum holes or bores H extend from the lower end of the spindle !2 in downwardly and outwardly inclined directions to the periphery of the annular slot M. A central opening I8 also extends from the s indle to the mold cavit The construction as thus far described is not new.

I have discovered that by forming an annular rece s 253 of suitable size, sha e and location, in the bottom face of the plate l 5,, a radical change is produced in the manner in which the glass operates when the mold with its charge of glass is withdrawn from the pool. When the melt. is

lowered into sealing contact with the supply body surface portion 23 which likewise chills an annular surface portion 24 of the glass with which it contacts during the gathering operation. This chilled ring of glass form a continuation of the chilled skin or layer 25 formed on the surface of the gathered charge which contacts with the mold walls. Between the chilled portions 2! and 24 is an annular surface portion 26 beneath the recess which is not brought in contact with the mold and therefore is not chilled but remains relatively hot and fluent.

As the mold is lifted with a charge of glass therein, as shown in Fig. 4, the column 21 of glass which unites the gathered charge 28 or blank with the supply body, is constricted or narrowedin to a much smaller diameter than the opening of the mold cavity. In this manner a substantially horizontal bottom surface 29 is formed on the blank 28, just below the bottom surface of the mold and uniting substantially at right angles with the vertical surface of the column or neck 2?. The gather of glass may be severed in a ggnventional manner by a knife or a pair of shears The operation by which the neck portion is so greatly constricted is dependent apparently upon the formation of the chilled annular surface portion 2! with a hot fluent annular surface 26 interposed between the chilled ring 2! and the gathered charge 28.

When the mold is lifted away from the pool, the blank of glass is held by suction in the mold and lifted therewith. Owing to the viscosity of the glass the column 21 is gradually formed and drawn upwardly, the glass comprised in this column being drawn from the molten supply body. Gravity exerts a downward pull opposing the upward movement of the column. lhe result of the several force acting on the glass is a neckingin. The inward movement of the glass which forms the column is apparentl localized by the chilled ring of glass 2! surrounding the more fluent surface portion so that the inward movement of glass during the formation of the column is largely from that portion of the supply body immediately beneath and adjacent to the surface 26. When the recess 29 is omitted, the chilled portion of glass covers the entire area between the mold cavity and the periphery of the mold which would interfere with such necking-in of the glass as the mold rises.

In order to obtain an effective necking-in of the glass, it is desirable to maintain the dimensions of the recess 20 and also the width of the annular surface portions 22 and 23 within certain prescribed limits. With a mold of the shape shown in the drawings and having a diameter of about 2 /4 inches, satisfactory results are obtained when the proportions shown in the drawings are maintained. In such a mold the groove 28 should be at least as wide as shown. Good results may be obtained with a wider groove but if of substantially less width it is comparatively ineffective. The width of the annular surface 22 may be greater than shown but should not be less. The width of the annular surface 23 should not be greater than shown and may be less, although any material reduction in this width may result in burning of the mold by the intensely hot molten glass.

Fig. 5 shows a somewhat modified construction adapted for forming a bottom flange or bead 32 on the blank 28. For this purpose the lower edge portion of the plate I l is cut away along the mold cavity surface It to provide an annular recess 33 in which the bead is formed. In this instance the vacuum slots l5 extend downward to said recess 33.

Modifications may be restorted to within the spirit and scope of my invention.

I claim:

1. A glass gathering mold having a downwardly opening mold cavity and a horizontal flat bottom, said bottom formed with an annular recess extending upwardly therein and spaced from and surrounding the mold cavity, the wall surface of said recess being continuous and imperforate throughout, so that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

2. A glass gathering mold having a downwardly opening circular mold cavity and formed with an annular recess in the bottom of the mold surrounding, spaced from and concentric with the mold cavity, the wall surface of said recess being continuous and imperforate throughout, so that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

3. A glass gathering mold having a downwardly opening circular mold cavity and formed with an annular recess in the bottom of the mold surrounding, spaced from and concentric with the mold cavity, the annular surface portion of the mold between said recess and the mold cavity being substantiall narrower than the said recess, the wall surface of said recess being continuous and imperforate throughout, so that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

4. A glass gathering mold having a downwardly opening circular mold cavity and formed with an annular recess in the bottom of the mold surrounding, spaced from and concentric with the mold cavity, the annular surface portion of the mold between said recess and the mold cavity being substantially narrower than the said recess, said bottom surface also including an annular portion surrounding said annular recess and of greater width than the recess, the wall surface of said recess being continuous and imperforate throughout, so that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

5. A suction gathering glass mold having a downwardly opening cup-shaped mold cavity, circular in cross section, the mold having a horizontal substantially fiat bottom, said bottom being formed with an annular recess concentric with and spaced from the mold cavity, the width of said recess at the bottom being materially greater than its depth, the wall surface of said recess bein continuous and imperforate throughout, so that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

6. A suction gathering glass mold having a downwardly opening cup-shaped mold cavity, circular in cross section, the mold having a horizontal substantially flat bottom, said bottom being formed with an annular recess concentric with and spaced from the mold cavity, the width of said recess at the bottom being materiall greater than its depth and greater than the distance between said recess and the mold cavity, the wall surface of said recess being continuous and imperforate throughout, o that the recess provides a sealed chamber when the mold bottom is in sealing contact with the glass.

7. A glass gathering mold having a downwardly opening circular mold cavity and formed with an annular recess in the bottom of the mold sur rounding, spaced from and concentric with the mold cavity, the mold being formed with an annular series of vertically disposed vacuum slots opening through the mold Walls into said mold cavity, said vacuum slots terminating at points above the bottom surface of the mold.

8. A glass gathering suction mold having a downwardly opening cup-shaped mold cavity, circular in cross section, the mold being formed with an annular recess in the bottom thereof surrounding, spaced from, and concentric with the mold cavity, the mold cavity Wall being formed with a recess extending throughout the circumference thereof closely adjacent to the bottom edge of said wall for forming an annular bead on the mold charge when the latter is drawn REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,223,392 Kadow Apr. 24, 1917 1,807,095 Treece May 26, 1931 1,986,449 Schutz Jan. 1, 1935 

